I know this question has been asked, but wanted to ask again as my situation is a bit different. I have a 2013 MacBook Pro and Logic X. This means my computer has no dedicated 1/8" mic jack (older models had the headphone jack double as a mic input; not the 2013 model). Besides getting a USB audio interface, which I will at some point, is there any way I can use Thumbjam with Logic X? Through wi-fi or bluetooth?

There's no good solution without more hardware. It's possible that you could use some of the airplay receiver software, but the latency would be absolutely terrible. Your best bet is still to get a USB audio interface.. they come in all shapes and prices, including ridiculously cheap.